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采用等离子束热源对40Cr表面进行硬化处理。利用扫描电镜和金相显微镜分析了硬化层的显微组织结构,并对硬化层进行显微硬度和耐磨性测试。结果表明:硬化区整体形貌呈月牙形,熔凝区组织形态为隐针马氏体+网状索氏体+残余奥氏体,相变淬火区组织为隐针马氏体+网状屈氏体+残余奥氏体+铁素体;其他工艺参数不变,随扫描速度的增大,硬化层深度和宽度减小,而最高硬度增加;沿硬化层层深的硬度分布规律是,从硬化层由表及里显微硬度先升高后降低,最高硬度在次表层;沿硬化层层宽的硬度分布规律是,硬化层中心部位硬度略有降低,向两侧硬度先升高后降低,直至40Cr基体硬度。硬化处理后试样耐磨性显著提高。
The 40Cr surface is hardened with a plasma beam heat source. The microstructure of the hardened layer was analyzed by scanning electron microscopy and metallographic microscope. The hardened layer was tested for its microhardness and wear resistance. The results show that the overall morphology of the hardened zone is crescent-shaped, the microstructure of the fused zone is hidden martensite + reticular sorbite + retained austenite, and the microstructure of the quenched zone in the phase transformation is hidden martensite + Martensite + retained austenite + ferrite; other process parameters remain unchanged, with the scan speed increases, the depth and width of the hardened layer decreases, while the maximum hardness increases; the distribution of hardness along the hardened layer depth is from The hardness of the hardened layer increases first and then decreases from the top and the bottom, and the highest hardness is on the subsurface. The distribution of the hardness along the hardened layer is that the hardness at the center of the hardened layer slightly decreases, , Until 40Cr matrix hardness. After the hardened sample wear resistance significantly increased.